Back to its 7th century origins.
Imams were allowed to preach their koran, but with limits imposed. To continue to preach, imams had to 'soften' the koran. For example, 'jihad' became a personal, spiritual battle, rather than a bloody fight of conquest against all others. This continued for several generation in some countries, many more in others. THIS is where willfully blind liberals like O'Venal get their talking points that islam is a 'religion of peace'. You will note that most WOGs, as they were known, who first came to GB after the independence of India and Pakistan and other Middle Eastern and South Asian former British colonies, were very much Westernized and fit in well in British society. It is now mostly the young, and new comers who vehemently opposed the West.
With the costs of WWI and WWII, the colonial powers had no money or desire to fund their far flung colonies, so they became independent states. Many have reverted to the original, blood thirsty version of islam. Others, like Turkey, are sliding down that path. Only Egypt has put a halt to its slide down that path. How long can the military hold onto a relatively 'peaceful', or at least less bloody islam? Who knows.
To those who have criticized the Europeans for their colonization of much of the world during the 18th through early 20th century, remember that the battle we are in against radical koranic islam, would have happened a century ago or more, were it not for the colonial efforts of the European powers, Great Britain, France, Netherlands, Germany, in previous centuries.
There has never been a civilization coexist with Islam...